JPH09254046A - Electric driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate wear, vibration, and noise due to impact and obtain large torque even if attractive force of magnets is small by constituting a clutch mechanism by a magnet clutch and arranging the magnet clutch between a motor and a decelerator. SOLUTION: A motor 1 as a power source and a gear case 3 are connected mutually by a mounting base 2, and a pin which is an output shaft of the motor 1 and an input shaft 1a of a transmission part in the gear case 3 which is a shaft 31 on driving side is press-fitted in a magnet clutch 6 and is fixed. The magnet clutch 6 consists of a magnet mounting plate 6a which fits and fixes the input shaft 1a, magnets 6b, 6c which are magnetized in such a manner that they form different poles alternately in the direction of a face of a disc which constitutes a clutch plate 33 on driving side and a clutch plate 34 on output side, and a magnet mounting plate 6d. By arranging the magnet clutch 6 between a deceleration mechanism 20 and the motor 1, transmission torque is reduced, and attractive force of magnets is reduced even when large torque is obtained in output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric driver provided with a speed reducer between a drive motor and an output shaft and a clutch mechanism for cutting off a driving force when a set torque is reached. By using the mechanism as a magnet clutch, while making good use of the magnet clutch, by reasonably setting the arrangement position of the magnet clutch, it is possible to obtain a large output torque even if the magnet attractive force in the magnet clutch is small. You can
Therefore, the present invention relates to a technique for reducing the size of the magnet, downsizing the magnet clutch, and downsizing the electric driver.

[0002]

2. Description of the Related Art Conventionally, in an electric driver equipped with a speed reducer between a driving motor and an output shaft, and a clutch mechanism for cutting off the driving force when a set torque is reached, an electric driver is provided between the motor and the output shaft. There is an electric screwdriver having a clutch mechanism that cuts off the transmission of driving force for the purpose of preventing damage to a screw or a member to be screwed and preventing overload of a motor.

Such an electric screwdriver has an urging spring, a steel ball urged by the urging spring, and a cam mountain whose relative rotation is restricted by the steel ball between the output shaft and the speed reducer. ,
There is a cam riding type clutch mechanism in which a steel ball urged by an urging spring rides on a cam ridge and does not transmit a rotational force when the load applied to the output shaft exceeds a set torque.

In addition, a mechanism for mechanically restraining relative rotation, allowing relative rotation and interrupting the driving force, such as a cam riding system, magnetically restrains relative rotation by a permanent magnet or an electromagnet, and outputs the output shaft. There is a torque limiter clutch system in which the magnetic attraction force cannot maintain the relative rotation constraint when the load reaches a certain set torque and the driving force is not transmitted to the output shaft.

[0005]

However, in the conventional cam riding type clutch mechanism, when a steel ball rides on a cam mountain, a noise is generated due to a collision, and a problem such as abrasion due to a collision with the cam mountain occurs. The clutch life will be shortened, and the clutch torque will change from the initial set torque.

The torque limiter clutch system is
Since the rotation is transmitted by the magnetic attraction force, it is difficult to transmit a large driving force as compared with the cam riding method. The present invention has been made in view of the above problems, and an object thereof is to use a magnet clutch as a clutch mechanism so that there is no wear or vibration and noise due to impact, and the goodness of the magnet clutch is utilized. By rationally setting the arrangement position of the magnet clutch, a large torque can be obtained in the output even if the attraction force of the magnet in the magnet clutch is small. Therefore, the magnet is made smaller and the magnet clutch is made smaller,
It is to provide an electric screwdriver that can be downsized as a whole.

[0007]

According to a first aspect of the present invention, a speed reducer 20 is provided between the driving motor 1 and the output shaft 18, and a clutch mechanism 19 that shuts off the driving force when the set torque is reached. It is an electric driver, and is characterized in that the clutch mechanism 19 is a magnet clutch 6 and the magnet clutch 6 is arranged between the motor 1 and the speed reducer 20.

In the second aspect of the present invention, the magnet clutch 6 is provided with a driving side clutch plate 33 and an output side clutch plate 34 on the driving side shaft 31 and the output side shaft 32, respectively. It is characterized in that at least one of the clutch plates 33 is provided with a magnetic force means so as to face each other with a gap d therebetween, and both clutch plates 33 and 34 are magnetically attracted and coupled at a predetermined transmission torque or less.

In the third aspect, each clutch plate 33,
34 is provided with magnets 6b and 6c having different polarities. According to a fourth aspect of the present invention, magnets having different polarities are alternately arranged on one clutch plate 33. According to a fifth aspect of the invention, the speed reducer 20 is an inscribed planetary speed reducer.

According to a sixth aspect of the present invention, the set torque in the magnet clutch 6 can be adjusted. According to a seventh aspect of the present invention, the magnetic clutch 6 can be brought into a clutch inoperable state (directly connected state). According to the present invention, a control circuit 29 for detecting the clutch slip of the magnet clutch 6 and stopping the driving force is provided.

In the invention according to claim 1, the number of parts can be reduced by using the magnet clutch 6 as the conventional clutch mechanism for riding the cam ridges, and there is no wear due to contact, so that the life is extended. Can
Further, in the invention according to claim 1, in particular, the magnet clutch 6 is arranged between the reduction mechanism 20 and the motor 1 while avoiding the noise of riding over the cam lobe and making it quiet. Since the torque transmitted to the magnet clutch 6 is smaller than that in the case where it is arranged between the reduction gear mechanism 20 and the output shaft 18, even if an attempt is made to obtain a large torque for the output, the attraction force of the magnet is weak. The size of the magnet clutch 6 can be reduced, and the size of the magnet clutch 6 can be reduced. As a result, the size of the electric driver can be reduced. You can

Further, the magnet clutch 6 is provided with a driving side clutch plate 33 and an output side clutch plate 34 on the driving side shaft 31 and the output side shaft 32, respectively.
Are preferably opposed to each other with a small gap d, and at least one clutch plate 33 is provided with a magnetic force means so that both clutch plates 33 and 34 are magnetically attracted and coupled with each other at a predetermined transmission torque or less. It is also preferable to provide the clutch plates 33, 34 with magnets 6b, 6c having different polarities, and one clutch plate 33 may have magnets 6b, 6 having different polarities.
It is also preferable to arrange c alternately.

According to the fifth aspect of the present invention, since the inscribed reduction gear mechanism has an eccentric shaft, the accuracy of the axial center error is required by the planetary gear reduction mechanism from the motor shaft center to the output shaft center. Since the magnet clutch 6 is non-contact, the axial center accuracy is not required, and the assembling property and the mass productivity can be improved, and the internal reduction mechanism saves space compared to the planetary reduction gear. Enables a high reduction ratio and reduces the size of the electric screwdriver.

According to the sixth aspect of the present invention, the torque of the magnet clutch 6 can be adjusted, and the clutch torque required by the operator who uses the electric screwdriver can be realized. In the invention according to claim 7, the clutch function can be eliminated and the clutch can be directly connected, and the degree of freedom of work can be increased. According to the eighth aspect, power can be saved by cutting off the power supply when the clutch slips at the completion of the work.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic sectional view showing the operating principle of the invention according to claim 1.

A motor 1 as a power source and a gear case 3 are connected by a mount 2, and an input shaft 1a of a transmission portion in the gear case 3 which is an output shaft of the motor 1 and serves as a driving side shaft 31. The pin is fixed to the magnet clutch 6 by press fitting. The magnet clutch 6
A magnet mounting plate 6a fitted and fixed to the input shaft 1a,
It is composed of magnets 6b and 6c magnetized so as to have different polarities alternately in the surface directions of the disks constituting the driving side clutch plate 33 and the output side clutch plate 34 as shown in FIG. 2, and a magnet mounting plate 6d. Has been done. Magnet mounting plate 6a, magnet 6b, magnet 6
c and the magnet mounting plate 6d are adhered to each other in a non-separable manner. A gap d is provided between both magnets 6b and 6c, and they are arranged so as not to come into contact with each other. Magnet mounting plate 6d and output side shaft 3
The rotary shaft 7 as 2 and the sun gear 8 are press-fitted and fixed so as to rotate integrally, and are held by the bearing 5. A sun gear 8, a planet gear 9, a ring gear 10, a pin 11, a carrier 12, a sun gear 13, a planet gear 14, a ring gear 15, a pin 16, and a carrier 17 are provided between the rotary shaft 7 and the output shaft 18 in two stages. It constitutes a well-known planetary gear mechanism, and the rotation from the rotary shaft 7 is greatly decelerated and taken out by the output shaft 18.
A well-known chuck (not shown) is attached to the output shaft 18, and a well-known screw fastener is attached to the chuck to form an electric screwdriver.

When a low load torque is applied to the output shaft 18 when tightening screws or the like, the rotational force transmitted by the motor 1 is transmitted to the magnet 6b via the magnet mounting plate 6a.
The attractive force between the magnets 6b and 6c transmits the rotational force to the magnet mounting plate 6d, and the rotational force decelerated by the planetary gear mechanism is transmitted to the output shaft 18. When tightening screws like this, for example, the head of the screw sits on the tightening surface,
When a high load torque is applied to the output shaft 18, both magnets 6b,
High torque cannot be transmitted by the attraction force of 6c, and only the magnet mounting plate 6a and the magnet 6b on the input side start idling, and a large load is not applied to the motor 1.

The magnet clutch 6 may be a contact type instead of a non-contact type. That is, one clutch plate (magnet 6b
Or 6c) is attached to the shaft (the input shaft 1a or the rotary shaft 7) in a non-rotatable and slidable manner, and when the torque exceeds a set value, one clutch plate slides away from the shaft and both clutch plates come into sliding contact. It may be configured so that it slips and the clutch disengages.

In the first embodiment as described above, the conventional cam mountain climbing system is used for the magnet clutch 6 using a magnet.
By doing so, it is possible to reduce the number of parts, and it is possible to prolong the service life because there is no wear due to contact. In particular, by arranging the magnet clutch 6 between the reduction gear mechanism 20 and the motor 1, the transmission torque is smaller than that between the reduction gear mechanism 20 and the output shaft 18, so that a large torque can be obtained in the output. Even when it is done, it is possible that the magnet attracting force is weak.
That is, the magnet can be made small, and the magnet can be an inexpensive magnet having a small magnetic flux density.
In FIG. 1, reference numeral 35 is a bearing and 36 is a watertight material.

(Embodiment 2) FIGS. 3 and 4 show the principle of operation in the invention according to claim 5. Instead of the planetary gear speed reduction mechanism as the speed reducer 20 of the first embodiment,
It uses an inscribed reduction mechanism. That is, the eccentric shaft 2
The rotary shaft 7 and the rotary shaft 7 are press-fitted into each other so as to be integrated with each other, and are configured to rotate integrally. Center 21p of eccentric shaft 21
Is deviated from the center 7p of the rotating shaft 7, the center axis of the planetary plate 22 and the center axis of the eccentric shaft 21 are arranged on the same axis, and the eccentric shaft 21 and the planetary plate 22 slide smoothly. Possible,
An eccentric amount is provided so that the planetary plate 22 and the ring gear 23 having a central axis on the same axis of the rotary shaft 7 and a gear formed on the inner circumference thereof are always inscribed. The planetary plate 22 is provided with a tooth profile so as to engage with the ring gear 23 and make a rotational contact without slipping. The planet plate 22 has a center 2 of the planet plate 22.
Opening hole 24 having a center on a concentric circle centered at 1p
At least two are provided, and the pin 16 is press-fitted and fixed to the carrier 17 integrated with the output shaft 18.
It is arranged so that it always contacts with.

As shown in FIGS. 4 (a) and 4 (b), when the rotational force transmitted by the magnet clutch 6 is transmitted to the eccentric shaft 21 through the rotary shaft 7 in the direction of arrow A, the planetary plate 22 is a ring. Since it rolls while contacting the gear 23, it rotates in the direction of arrow B around the central axis of the planetary plate 22. With the rotation of the planetary plate 22, the opening hole 24 transmits the rotational force to the pin 16 in the arrow B direction in FIG. 4B, and transmits the decelerated rotational force to the output shaft 18.

In the structure of the second embodiment, since the inscribed reduction gear mechanism has the eccentric shaft 21, the axis center of the planetary gear reduction mechanism from the shaft center of the motor 1 to the shaft center of the output shaft 18. Although the accuracy of the error is required, since the magnet clutch 6 is non-contact, the axial center accuracy is not required,
This makes it possible to improve the ease of assembly and mass production, and the inward reduction gear mechanism enables space-saving high reduction compared to the planetary reduction gear, and the electric driver can be downsized. That is, it is possible to configure a pencil-type electric screwdriver.

(Embodiment 3) FIG. 5 is a diagram showing the principle of operation in the invention according to claims 6 and 7.
An adjustment handle 25 is provided on the gear case 3 so that only relative rotation is possible, and the adjustment handle 25 and the bearing holder 4 are engaged with each other by a screw. Then, by rotating the adjustment handle 25, the bearing holder 4 is moved in the axial direction,
The gap d between the magnets 6b and 6c of the magnet clutch 6 is adjustable.

Further, the magnet mounting bases 6a and 6d of the magnet clutch 6 are formed with concave and convex portions 37 and 37 capable of engaging with each other, and the adjustment handle 25 is provided with a gap d between the magnets 6b and 6c. When the magnets 6 are rotated in a narrower direction, the concavo-convex portions 37 and 37 are meshed with each other, the magnet mounts 6a and 6d are coupled to each other, the clutch operation of the magnet clutch 6 is disabled, and the input and output of the magnet clutch 6 are turned off. The same configuration is used so that a direct connection state is possible.

In the third embodiment, the torque of the magnetic clutch 6 can be adjusted, the clutch torque required by a working vehicle using an electric driver can be realized, and the clutch function can be disabled to directly connect the clutch. The degree of freedom of work can be increased. (Embodiment 4) FIG. 6 shows the principle of operation in the invention according to claim 8.

Hall elements 26 and 27 are arranged on a line parallel to the central axis of the magnet clutch 6 so as to face the outer circumferences of the magnets 6b and 6c of the magnet clutch 6, and it is possible to detect the rotation of the magnets 6b and 6c. When the magnetic clutch 6 is transmitting rotation without slipping, the signals detected by the Hall elements 26 and 27 are the same signal, and when the magnetic clutch 6 is activated at the completion of the screw tightening work, that is, on the input side. When the magnet mounting plate 6a and the magnet 6b rotate and the magnet 6c and the magnet mounting plate 6d stop, different signals are detected by the Hall elements 26 and 27. Such Hall elements 26, 27
By comparing and detecting the detected signal with a comparison circuit, etc., and inputting the detected signal as an input signal of the motor operation control circuit such as a relay, an electric screwdriver that can stop the power when the screw tightening is completed is configured. are doing.

In such an embodiment, it is possible to stop the motor 1 when the magnet clutch 6 is activated, so that the electric power of the electric driver can be saved. (Embodiment 5) FIGS. 7 and 8 are diagrams showing the principle of operation.

A Hall element 26 'is arranged on the outer periphery of the magnet 6b (or the magnet 6c) of the magnet clutch 6.
The Hall element 26 'can detect a change in magnetic flux when the magnet 6b (or the magnet 6c) of the magnet clutch 6 rotates. The change in the magnetic flux when the magnet 6b (or the magnet 6c) of the magnet clutch 6 rotates depends on the change in the rotation speed of the magnet 6b (or the magnet 6c) of the magnet clutch 6. Therefore, the Hall element 26 'causes the magnet 6b (or the magnet 6c) of the magnet clutch 6 to operate.
Detects the change in magnetic flux when the
It is possible to detect the rotation speed of the motor 1.

FIG. 8 shows a motor 1 as a power source and the motor 1.
3 is a block diagram of a power supply circuit configured by a power source 28 that supplies power to the motor 1 and a control circuit 29 that controls adjustment of power supplied to the motor 1. FIG. Then, the hall element 26 '
The rotation signal N detected by the control circuit 29 is input to the control circuit 29, and the control circuit 29 causes the target rotation speed signal Hall element 26 '.
By adjusting the electric power supplied from the electric power source 28 to the motor 1 so as to match the rotation signal detected by the motor 1
It is possible to control the rotation speed of the.

That is, in the fifth embodiment, the magnet 6b (or the magnet 6c) of the magnet clutch 6 is used,
It is possible to adjust the output rotation of the electric screwdriver by detecting the number of rotations of this, and it is possible to perform work that requires low-speed rotation, such as work to start screw tightening or drilling. As described above, since the magnet 6b (or the magnet 6c) of the magnet clutch 6 is used for detecting the rotation speed, the configuration for detecting the rotation speed can be simplified.

[0031]

According to the first aspect of the present invention, there is provided an electric driver having a speed reducer between a driving motor and an output shaft and a clutch mechanism for cutting off the driving force when a set torque is reached. Since the clutch mechanism is a magnetic clutch and the magnet clutch is arranged between the motor and the speed reducer, the number of parts can be reduced by using the conventional clutch mechanism of riding the cam ridge as a magnetic clutch. Further, since there is no wear due to contact, it is possible to prolong the service life, and it is possible to avoid the noise that runs over the cam ridge and to make it quiet. In particular, in the invention according to claim 1, the magnet clutch is provided with a speed reduction mechanism and a motor. Between the speed reduction mechanism and the output shaft, the magnetic clutch Since the torque transmitted to the coil is small, even when trying to obtain a large torque for the output, it is possible to make the magnet's attractive force weak, and it is possible to make the magnet small and reduce the magnetic flux density. There is an advantage that it is possible to use a small and inexpensive magnet, the size of the magnet clutch can be reduced, and as a result, the size of the electric driver can be reduced.

Further, in the magnet clutch, a driving side shaft and an output side shaft are respectively provided with a driving side clutch plate and an output side clutch plate, and both clutch plates are opposed to each other with a small gap therebetween, and at least one clutch plate is provided. By providing magnetic means,
It is also preferable that both clutch plates are magnetically attracted and coupled with each other at a predetermined transmission torque or less, and it is also preferable to provide each clutch plate with magnets having different polarities. Also, one clutch plate is alternately magnetized with different polarities. It is also preferable to arrange in

According to the fifth aspect of the invention, since the speed reducer is an inscribed planetary speed reducer, the internal speed reduction mechanism has an eccentric shaft, so that the planetary gear from the motor shaft center to the output shaft center. The accuracy of the shaft center error is required by the reduction mechanism, but since the magnetic clutch is non-contact, the shaft center accuracy is not required, and the assemblability and mass productivity can be improved. Compared to the planetary speed reducer, the speed reduction mechanism can save space and achieve a high reduction ratio, and the electric driver can be further downsized.

In the invention according to claim 6, since the set torque in the magnet clutch can be adjusted, the torque of the magnet clutch can be adjusted and the clutch torque required by the operator using the electric screwdriver can be realized. There is an advantage. In the invention according to claim 7, since the clutch inoperable state (directly connected state) of the magnet clutch is enabled, there is an advantage that the clutch function can be eliminated and the clutch can be directly connected, and the degree of freedom of work can be increased. is there.

In the eighth aspect, since the control circuit for detecting the clutch slip of the magnet clutch and stopping the driving force is provided, the energization when the clutch slips is cut off,
There is an advantage that power saving can be achieved.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and claims 1 to 4
3 is a schematic cross-sectional view showing the operation principle of the invention according to FIG.

FIG. 2 is a partial perspective view of the invention according to claims 1 to 4 of the same.

FIG. 3 is a schematic sectional view showing the operating principle of the invention according to claim 5 of the same.

4 (a) and (b) are schematic sectional views showing the operating principle of the invention according to claim 5 of the same.

FIG. 5 is a schematic sectional view showing the operation principle of the invention according to claim 6 and claim 7 above.

FIG. 6 is a schematic sectional view showing an operating principle of the invention according to claim 8 of the same.

FIG. 7 is a schematic sectional view showing the operating principle of the fifth embodiment of the above.

FIG. 8 is a block circuit diagram of the same.

[Explanation of symbols]

 1 Motor 6 Magnet Clutch 18 Output Shaft 19 Clutch Mechanism 20 Reducer

Claims (8)

[Claims] 1. An electric driver having a reducer between a drive motor and an output shaft, and a clutch mechanism for cutting off the driving force when a set torque is reached, wherein the clutch mechanism is a magnetic clutch. An electric driver characterized in that a magnet clutch is arranged between the motor and the speed reducer. 2. A magnet clutch is provided with a drive side clutch plate and an output side clutch plate on a drive side shaft and an output side shaft, respectively, and both clutch plates are opposed to each other with a small gap, and at least one clutch plate is provided. 2. The electric screwdriver according to claim 1, wherein magnetic force means is provided to magnetically attract and couple both clutch plates at a predetermined transmission torque or less. 3. The electric screwdriver according to claim 2, wherein each clutch plate is provided with magnets having different polarities. 4. The electric screwdriver according to claim 3, wherein magnets having different polarities are alternately arranged on one clutch plate. 5. The electric screwdriver according to claim 1, wherein the reduction gear is an inscribed planetary reduction gear. 6. The electric screwdriver according to claim 1, wherein the set torque of the magnet clutch is adjustable. 7. The electric screwdriver according to claim 1, wherein the magnetic clutch is capable of being in a clutch inoperable state (directly connected state). 8. The electric driver according to claim 1, further comprising a control circuit that detects a clutch slip of the magnet clutch and stops the driving force.